(1) Field of the Invention
This invention relates to an encircled electrical compression contact.
The present invention is particularly suitable for, but not limited to, a contact adapted to co-operate with a complementary cylindrical contact to enable electrical continuity between two mating electronic assemblies. Such assemblies include planar electronic printed circuit board assemblies, flexible connectors and circuit cables used in the computer and telecommunications industries, eg., in disk drives or wireless phone apparatus.
(2) Prior Art
Electrical contacts are commonly used to electrically interface two circuit boards or similar substrates, or a circuit board to a circuit cable. Such contacts commonly incorporate an insulated connector body, where an electrically-conductive path extends through the body from a terminal at one face (connected by a soldering process to a second printed circuit board or to a conductive wire or lead in a cable) to a conductive metal contact, extending from the opposite face, releasably engageable in a complementary cylindrical contact or like conductive device (eg., in the substrate of a printed circuit board).
The metal contact is encircled in the cylindrical contact and is compressed thereby. This type of encircled compression contact is particularly useful for joining noise sensitive circuits with the minimal length of electrically conductive path between the two circuits.
In applications such as in disk drives or wireless phone apparatus, it is often desirable to provide electrical continuity between a flexible printed circuit board cable and a rigid printed circuit board. In such applications, all the forces on the compression contact are applied along the longitudinal axis of the contact to the surface of the rigid printed circuit board. The electrical connection is then generated by the longitudinal force applied by the compression contact to the terminal pads, leads or similar conductive attachments on a printed wiring board.
A connector can include any number of compression contacts or pins, typically twenty (20) or more. The strong longitudinal loads applied by all the compression contacts can create soldered joint fatigue on the components directly aligned with or adjacent the printed circuit board. The containment, or control, of such forces is difficult and can be expensive, especially as the number of compression contacts on a printed circuit board, or in a cable connector, increases, thereby compromising the reliability of the electrical compactor between the two electronic components.
It is an object of the present invention to provide an encircled compression contact where the longitudinal forces are minimised.
It is a preferred object of the invention to provide such a contact where the compression forces are substantially transverse to the longitudinal axis of the contact.
It is a further preferred object to provide such a contact which can be easily inserted in, and accurately located relative to, the cylindrical (encircling) contact.
It is a still further preferred object to provide such contacts which can be easily fabricated and incorporated into moulded insulated housings or connector bodies at a high volume rate.
It is a still further preferred object to provide an electronic component (eg., circuit board or cable connector) incorporating one or more of the contacts.
Other preferred objects will become apparent from the following description.
In one aspect, the present invention resides in an encircled compression contact for an electrical component, the compression contact being formed of electrically conductive material, the compression contact including:
a bottom portion, receivable in an electrically insulating support and connectable to an electrical circuit;
a top portion, spaced from the bottom portion, configured for insertion into an encircling contact; and
a pair of body portions interconnecting the top and bottom portions and having opposed contact faces, so arranged that when the compression contact is inserted into the encircling contact, the compression forces are transverse to a longitudinal axis of the compression contact and urge the contact faces into electrical contact with the encircling contact.
Preferably, the bottom portion extends between opposed surfaces of the insulating support and creates the compression forces for the contact faces.
Preferably, the top portion is configured for insertion into the encircling contact and has a bottom wall engageable with an end face of the encircling contact.
Preferably, each contact face has a shoulder, spaced from the bottom wall of the top portion, engageable with an opposed end face of the encircling contact.
Preferably, the body portions are substantially planar and are offset so that, when the contact faces are compressed inwardly as the compression contact is inserted into the encircling contact, adjacent faces of the body portions slide over each other.
Preferably, the compression contact is formed from a single strip of electrically conductive material selected from stainless steel, cooper or phosphorous bronze.
In a second aspect, the present invention resides in an encircled electrical compression contact assembly including:
a compression assembly as hereinbefore described; and
an encircling contact, formed of electrically conductive material, the encircling contact having a cylindrical body, with an internal contact face engageable with the contact faces of the compression contact, the cylindrical body extending between opposed surfaces of a rigid supporting substrate.
In a third aspect, the present invention resides in an electrical connector or component having:
a body or support of electrically insulating material; and
at least one of the compression contacts as hereinbefore described, the bottom portion of the or each compression contact being received in the body or support.